Sewage Treatment and Recycle
Aug 04, 2015
What is sewage?
Sewage is the wastewater originating in homes from
• Kitchen• Laundry• Wash Basins• Bath rooms & Toilets• Floor WashIn one word, it is all the wastewater that
comes out of homes / human use
Where does it all go!
Where does the water from the washer go?
When you flush the toilet where does the contents go?
By gravity flow, the waste is on its way to your local wastewater treatment plant!
Sewage composition ….• Solids like vegetable peelings, rice, plastic
covers etc• Oil & Grease from Kitchen / Laundry• Suspended solids from kitchen• Chemicals from detergents• Mild colors from laundry / food• Pathogenic microbes from fecal matterPhysical impurities, dissolved chemical
impurities & Microbiological impurities
Hazards of wastewater?
• 34 Lakh children die every year due to water borne diseases. 99% of this are from developing countries
• That is every one child every 21 seconds
• Water borne diseases originate from human execrate
Why treat wastewater?
• Causes a demand for dissolved oxygen (lowers DO levels of streams)
• Adds nutrients (nitrate and phosphate) that cause excessive growth
• Stinks otherwise• Increases suspended solids or
sediments in streams (turbidity increase)
• To comply with Environmental norms
Levels of Treatment
Primary– removal by physical separation of grit and
large objects (material to landfill for disposal)
Secondary– aerobic microbiological process (sludge)
organic matter + O2 CO2 + NH3 + H2O
NH3 NO3-
- lowers suspended solids content (into sludge)
aquatic nutrient
Mostly dead microbes
Aeration and
rapid mixing
Settlingcollects sludge
on bottom
Secondary process
airdiffuser
From
pri
mary
pro
cess
To te
rtiary
pro
cess
Levels of Treatment continuedTertiary (advanced)– anaerobic microbiological process with a
different microbe where O2 is toxic (more sludge)
NO3- N2 (escapes to atmosphere)
– PO4-3 if not removed in sludge in secondary
processPO4
-3 + Al+3 AlPO4 (s) (into sludge)
- aeration to strip N2 and re-oxygenate (add DO)
Slow mixingto keep
suspended and O2 out
Settlingcollects sludge
on bottom
Tertiary processFr
om
seco
ndary
pro
cess
Effl
uent
add methanol as food source
When the treatment is done…
• Effluent back to stream after– Chlorination / de-chlorination and– a final carbon filtration
• For re-use advanced filtration methods Ultra-Filtration
• Sludge – very nutrient rich– applied directly to land as fertilizer– incinerated (good fuel after drying)– composted (good manure)
Contact us…
PLOT NO. 201/7 PHASE-IIIDA CHERLAPALLY, HYDERABAD- 051
Customer Care: 0-806-1344-798www.modernstp.com
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